Conventionally known is a refrigerant packaging an aqueous solution of potassium chloride, ammonium chloride, and the like as a cold-storage agent (Patent Literature 1 and Patent Literature 2).
Also, in a case of using a refrigerant to preserve a frozen food, the refrigerant is in a form of a packaged refrigerant packaged in a plastic package (Patent Literature 3). Currently, a refrigerated container using ice, dry ice, or a pump is the mainstream. Also, in a case of transporting a refrigerated target such as a food in a current refrigerated transportation field site, an equipped cooling device cools the entirety inside a truck to retain a refrigerating temperature for a food or the like and transport the food or the like.